Fluid rheostat



B. F. TILLSON.

FLUID RHEOSTAT.

APPLICATION FILED saw. 15. 1920.

Patented May 23, 1922.

INVENTOR Rmumn.

ATTORNEY Cir BENJAMIN F. 'IILLSON, 0F FRANKLIN, NEW JERSEY.

FLUID RHEOSTAT.

Specification of Letters Patent.

Patented May 23-, 1922.

Application filed September 15, 1920. Serial No. 410,451.

To all to 710m it may concern Be it known that I, BENJAMIN F. TILLSON, a citizen. of the United States, residing at Franklin, in the county of Sussex and State of Yew Jersey, have invented new and useful Improvements in Fluid Rheostats, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawing, iorming a part of this specification.

This invention relates to fluid rheostats and more particularly to temperature regulating means therefor.

As is well known, the ohmic resistance 01: an electrolyte changes with variations in temperature thereof whereas the temperature of a fluid rheostat including its electrolyte may vary widely under different service conditions. Thus the actual resistance of the rheostat is dependent not only upon the immersed plate area and the length and number of current paths but is moreover largely influenced by the electrolyte temperature, and the present invention has among its ob jects that of minimizing variations or aberrations due to such influence in the resistance of such rheostats.

Another object is that of providing for substantial elimination or material reduction of temperature changes due to variable service requirements of such rheostats.

Another object is that of providing means sensitive to variations in temperature oi the electrolyte for automatically reducing the range of such variations and tending to re store such temperature to a normal or given value while also effecting conservation of cooling fluid.

Other objects and advantages will hereinai'ter appear.

The accompanying drawing, which consists of a single figure, illustrates diagram- 'matically one of the embodiments which the invention may assume in practice.

Referring to the drawing, the same illustrates a fluid rheostat having electrodes 5 to be immersed in an electrolyte 6 and provided with coils indicated at 7 to be supplied with cooling water from a suitable source through an intake pipe 8, a suitable discharge conduit 9 being also provided. A regulating valve 10 is arranged to control the passage in said intake p'ipe and provided with an adjustable spring 11 tending to close said valve, while a temperature responsive element 12 is arranged within the rheostat to be surrounded by the electrolyte 6 for subjection to the temperature conditions of the latter, said element having an operative con nection with the valve 10 providing for actuation of the latter.

In practice the element 12 may advanta geously comprise a container having therein a quantity of fluid adapted to undergo marked volumetric or pressure changes in response to temperature variations.

The valve 10 is provided with a stem 13 preferably located within the spring 11 and terminally connected with a flexible diaphragm 14 arranged to constitute a portion of the enclosing wall of a pressure chamber indicated at 15. A pipe 16 serves to connect said chamber with the interior of the element 12 for subjecting the former to the pressure conditions obtaining within the latter.

Upon passage of current through the rheostat the temperature of the electrolyte and of the thermostatic element 12 immersed therein is adapted to rise thus increasing the pressure of the fluid within said element, such i11- creased pressure being transmitted through the pipe 16 to the chamber 15. Such action serves to force the diaphragm 14 outwardly for opening the valve 10 against the force of the spring 11 and to a degree determined by the value of the rise in temperature of the electrolyte. Such opening of said valve serves to admit a suitable flow of cooling water to the coils 7 for reducing said temperature.

Conversely, interruption of the supply of current to the rheostat or reduction of the flow of current below a minimum value serves to effect closure of said valve. By suitably adjusting the force of the spring 11 with reference to the pressure within the chamber 15 the devioemay be calibrated to maintain the temperature of the electrolyte substantially constant irrespective of relatively wide variations in value of the current flowing.

The foregoing arrangement thus provides for full automatic control of the suonlv of cooling water and for overcoming resistance variations of the rheostat due to tempcraturc changes. iilso the 2iinY'(!=.'lQH lll)Ot.l automatic closure oi. the valve when the te1uperature below a given value serves to ell'ect a marl'ied saving in consumption ot cooling water.

lVhat 1 claim as new and desire to secure by Letters Patent is:

1. A fluid rheostat having means sensitive to 'ariations in temperature of said rheostat to automatically compensate for such *ariations.

2. A. fluid rheostat having a tl'iermostatic (len ent subjected to intisici'lce in accordance with the temperature conditions o'l said rheostat and temperature varying means .tor the rheostat subjected to control by said thermostatic element.

3. In a fluid rheostat the combination. with temperature varying means for the rheostat, of control means for said. former means snh jected to influence in accordance with the temperature condition of said rheestat for maintaining the temperature substantially constant irrespective of variations in value ot the electrical energy dissipated in the rheostat.

l. In a fluid rheostat the combination with coils to be supplied with fluid for cooling the rheostat electrolyte oi a valve to control the supply of cooling fluid to said coils and control means for said valve comprising a thermostatic element subjected to the tel s perature conditions of said electrolyte.

In a tluid rheostat, the combination. with coils to be supplied with fluid for cooling; the rheostat electrolyte, of a valve to control the supply of cooling iluid to said coils and control means for said valve comprising a spring tending to maintain said valve closed, a pres-- sure responsive device -for opening said. valve and a thermostatic element subjected to the temperature conditions o'l said electrolyte for controlling the action of said. pressure responsive device.

In witness whereof I have hereuntosul scribed my name.

BEN). F. TILLSON 

